# Generating the data model dynamically

## Use case

Let's assume that we want to understand the distribution of orders by their statuses.
Let's imagine that new order statuses can be added in the future, or we get a list of
statuses from an external API. To calculate the orders percentage distribution, we need
to create several [measures][ref-measures] that refer to each other. But we don't want
to manually change the data model for each new status.

## Data modeling

To calculate the number of orders as a percentage, we need to know the total
number of orders and the number of orders with the desired status. We'll create
two measures for this. To calculate a percentage, we'll create a measure that
refers to another measure.

```javascript
const statuses = ["processing", "shipped", "completed"]

const createTotalByStatusMeasure = (status) => ({
  [`total_${status}_orders`]: {
    title: `Total ${status} orders`,
    type: `count`,
    filters: [
      {
        sql: (CUBE) => `${CUBE}."status" = '${status}'`
      }
    ]
  }
})

const createPercentageMeasure = (status) => ({
  [`percentage_of_${status}`]: {
    title: `Percentage of ${status} orders`,
    type: `number`,
    format: `percent`,
    sql: (CUBE) =>
      `ROUND(${CUBE[`total_${status}_orders`]}::NUMERIC / ${
        CUBE.total_orders
      }::NUMERIC * 100.0, 2)`
  }
})

cube(`orders`, {
  sql_table: `orders`,

  measures: Object.assign(
    {
      total_orders: {
        type: `count`,
        title: `Total orders`
      }
    },
    statuses.reduce(
      (all, status) => ({
        ...all,
        ...createTotalByStatusMeasure(status),
        ...createPercentageMeasure(status)
      }),
      {}
    )
  )
})
```

## Result

Using the measures defined above, we can explore the orders percentage
distribution and easily create new measures just by adding a new status.

```javascript
[
  {
    "orders.percentage_of_processing": "33.54",
    "orders.percentage_of_shipped": "33.00",
    "orders.percentage_of_completed": "33.46"
  }
]
```

## Source code

Please feel free to check out the
[full source code](https://github.com/cube-js/cube/tree/master/examples/recipes/referencing-dynamic-measures)
or run it with the `docker-compose up` command. You'll see the result, including
queried data, in the console.


[ref-measures]: /product/data-modeling/concepts#measures